The 15-year-old, who has not been named, was one of four who were camping close to Derwent Vale Primary School in Great Clifton near Workington.

The three others boys are being treated for the inhalation of fumes at the town's West Cumberland Hospital.

A Cumbria Police spokesman said attending officers, who were alerted by paramedics, reported a strong smell of petrol at the scene.

Det Ch Insp Barry Carruthers said: "We believe that four teenage local males were camping in the riverside area and tragically, when emergency services were called to the scene at about 1pm on Thursday, a teenage male was found dead.

"When we attended, there was a very strong smell of petrol at the scene and the three other teenagers have now been admitted to hospital for treatment for the inhalation of fumes.

"We are investigating whether fume inhalation was a direct factor in his death and are working to formally identify him and inform his close family and friends."